Mr Lansley told the BBC Politics Show the Government-set measures on waiting times had led to patients being treated according to the target rather than their needs.

He said: "The effect of it is to distort the judgments that doctors should be making and the NHS should be making about which patients should be treated first and how quickly they should be treated.

"We've reached the absurd situation where waiting time targets are being turned into a minimum wait so you've got local NHS bodies telling the hospitals that they can't treat patients before, say, 20 weeks because they can't afford to pay for it and because the waiting time target says they should be seen at 20 weeks."

Mr Lansley said the Conservatives would move to a situation where local hospitals published how long it would take to wait for a specific procedure.

He said: "They should be publishing how quickly they can see you. It shouldn't be 18 or 20 weeks, maybe it should be considerably less than that.

"That would be like a local contract and those local targets are more important than the national ones. One-size fits all targets aren't the right way forward.

"We need local targets which are set by doctors and hospitals and those local targets wouldn't try to say we must have an 18 week target for everywhere in the country."

Mr Lansley proposed a situation where performance is measured by looking at the long-term outcomes for patients rather than the time taken to have a procedure.

He said: "The waiting time target on cancer is the time to the first treatment.

"If you look at people with breast cancer, quite often they have surgery first and radiotherapy after.

"The waiting time for surgery has gone down because it's the first treatment; the waiting time for radiotherapy went up.

"We should target outcomes and the outcomes for cancer are things like five-year survival rate and in too many instances our five-year survival rates are below the European average and in relation to some things way below the American average."

He added: "These are objectives, not targets. A target says you narrow in on a specific part of the whole patient pathway.

"What we are saying is the NHS should be measuring the overall outcome."

Under the Conservative proposals, all GPs would be given the responsibility to purchase services for their patients.

He said: "Putting together the clinical decisions about what's right for patients with the budgetary consequences and setting those sorts of local priorities, that's the sort of thing GPs should be doing.

"They are senior professionals who are best placed to work out what is in the best interests of their patients."

Mr Cameron made his comments about cannabis in a video message on his internet site webcameron.

Responding to a question posed by a visitor to the website, he said: "If it could be proved there was a real medicinal benefit I would be relaxed by that.

"Politicians should be guided by the science and evidence and we should make the decision.

"My decision would be to license it if we can prove the medicinal benefits."

But Cameron was firm on his stance that cannabis should not be legalised for recreational use.

"I don't believe cannabis should be legalised," he said.

"It is right that it's criminal because if you decriminalise you increase the availability and make it more difficult for parents who are trying to keep their children away from drugs."